Early spring is considered a good time to plant perennials. Planting early, just after killing frosts have passed, is better than planting later in the spring, as the plants have more time to adjust befor warm weather arrives. Large container grown plants will bloom the first year. Perennials started from seed in January and February will be small plants in late spring. These can be planted in April and May. However, many will not bloom much the first year and, in some cases, will not bloom at all until the next year.
Although spring is when we all get the gardening fever, fall is a good planting time and is considered the best time to plant perennials in the South. As a rule, plant at least 6 weeks before hard-freezing weather occurs. Perennials planted in the fall produce an good root system during fall and early spring, enabling them to firmly establish growth before hot weather begins.
Preparing the soil is probably the single most important factor in growing perennials successfully. Adding organic matter (composted leaves, peat moss, aged manure) to the soil makes it much easier for you to plant in and for the plants to grow in.
If plants are pot-bound at planting time, loosen the roots around the bottom and sides of the root ball and spread them out in the bottom of the planting hole. Cover and firm the soil lightly around the plant. Be sure the base of the plant is at or slightly above ground level. After planting, mulch the planting area with 4 to 6 inches of mulch (pine straw, pine bark, straw, or grain or nut hulls). .
Unlike established trees and shrubs, most herbaceous perennials can be transplanted from one location in the garden to a new location with reasonable care. Transplanting is usually safest in the early spring when growth starts or in the fall once the foliage dies back.
Two important secrets to growing perennials successfully are watering and controlling weeds. After planting, thoroughly water the plants. While plants are becoming established, watering is necessary every couple of days. Never allow the soil to totally dry out.
Weeds crowd out perennials and make them less attractive. Mulching and hand weeding are the best ways to combat weeds. Mulch perennials after planting to suppress weeds and hold in moisture.